Volumetric and Diffusion Tensor Imaging biomarkers indicating long lasting post-concussion abnormalities in a youth pig model of mild Traumatic Brain Injury

Mild Traumatic Brain Injury (mTBI) caused by sports-related incidents in children and youth can lead to prolonged cognitive impairments, underscoring the importance of improved diagnosis and comprehension of its enduring impacts on neuropathology. A pig model was chosen for its similarities to the human brain in terms of gyrencephalic structure, size, and regional proportions, and a closed-head mTBI was induced in adolescent pigs. In this study, 12 (n=4 male and n=8 female) 16-weeks old Yucatan pigs were tested; n=6 received mTBI and n=6 received a Sham procedure. This study utilized T1-weighted imaging to assess volumetric alterations in different regions of the brain and diffusion tensor imaging (DTI) to examine microstructural damage in white matter. The pigs were imaged at one and three months post-injury. Our volumetric analysis of key white and gray matter regions showed significant longitudinal changes in pigs with mTBI compared to sham controls. The observed volume increases may be attributed to swelling, neuroinflammation, or hyperactivity. Fractional anisotropy (FA) values derived from DTI images demonstrated an increase in corpus callosum from 1 month to 3 months only in mTBI pigs. Additionally, comparisons of the left and right internal capsules revealed a decrease in FA in the right internal capsule for mTBI pigs, likely due to the impact being slightly localized to the right side of the brain, which may indicate demyelination. Thus, the injury has disrupted the maturation of white and gray matter of the developing brain. This signifies the need for longitudinal investigations after mTBI to comprehensively assess its long-term effects and contribute to the clinical management of concussion in youth.